1. Field of the Invention
The present invention relates to the mounting of an optical element to a substrate, and particularly but not exclusively to the joining of an optic fibre to a substrate and to coupling of an optic fibre to a further optical element located in or on a substrate.
2. Description of the Art
A number of techniques are known for coupling an optic fibre to an on-chip optical waveguide or chip facet. The most common approach is to align the fibre and to secure it in place by the use of a UV-curing epoxy adhesive. Alignment is achieved merely by butting the end of the fibre to the waveguide/chip facet, or, for better location, by securing the fibre with adhesive within a V-groove in the chip. One of the major problems associated with the use of epoxy adhesives is that they can degrade over time due to temperature cycling and ageing effects, causing misalignment between fibre and waveguide/chip facet.
In “Silicon Nitride Micro-Clips for the Kinematic Location of Optic Fibres in Silicon V-shaped grooves”, R M Bostock et al, J Micromech & Microeng, 8 (1998), page 343, there is reported a technique in which flexible clips are surface-machined out of silicon nitride and are used to hold a fibre in place in a V-groove. However, there are disadvantages in that micro-manipulation is necessary to insert the fibre beneath the clips, and multiple process steps are required to form the clips in the first place.
The prior art techniques mentioned above rely on manual or semi-automated alignment and are time-consuming.